The present invention relates to methods and apparatus for preparing a contaminated surface to receive a coating intended to be adhered to the surface and more particularly to methods and apparatus for removing contaminants from a surface intended to receive a finish coating such as paint.
The manufacture of articles that require the application of a finishing coating (such as paint) to the article, typically requires the removal of contaminants from the article's surface before the finish coat is applied to the article's surface. For example, in an automotive assembly line, workers rub down the exterior of the vehicle body with solvents that remove contaminants prior to sending the vehicle body to be painted. Typically, the containers dispensing the solvents are mounted on pivots so that the workers can hold a rag at the mouth of the container while tipping the container so as to dispense the solvent onto the rag. The worker then manually rubs the surface with the solvent-soaked rag to remove the contaminants from the surface of the vehicle that is to be painted.
These liquid solvents are compositions that include volatile organic compounds (VOC's) such as isopropyl alcohol and naptha, as well other materials such as deionized or purified water. The solvent compositions typically include other ingredients such as dipropylene glycol monomethylether (DPM). These compositions usually are mixed by the workers themselves, and the particular formulation is chosen depending upon the type of finish coating that is to be applied to the surface of the vehicle. For example, if a water-based paint is to be applied, the main solvent ingredient is isopropyl alcohol. For a solvent-based paint, the main solvent is naptha. However, controlling the proportion of these main ingredients in the solvent composition used by the workers can become problematic as such control becomes based on the skill of the worker who prepares the solvent composition. Similarly, the amount of solvent applied to the surface by the worker with the wiper that the worker has soaked with solvents dispensed from the pivoting container mouth is difficult to control. The control of these factors is desirable from the standpoints of the cost of the solvents, the effectiveness of their application to the surface for removing contaminants, and minimizing the solvent concentration in the atmosphere of the workers' environment. The latter involves both the health of the workers who are breathing this atmosphere and the safety of the workers in an environment where volatile liquids such as solvents may pose a fire hazard. Additionally, it is well known that reducing VOC's released to the atmosphere poses a positive impact on the environment.
Resealable dispensers of wipers saturated with VOC's are known, and one type is shown in FIG. 1 is described as follows. A resealable thin package, generally indicated by the numeral 10, includes a top panel 12 disposed opposite a bottom panel (not visible) and joined to one another at their peripheral edges 14 as by heat sealing and forming a receptacle 15 therebetween. Each of the top and bottom panels is composed of an outer layer formed of a sheet of polyester material that is contact-laminated to an inner layer formed of a sheet of polyethylene material. The top panel is provided with an elongated through-cut 16 that forms a flap 18, which remains attached to top panel 12 by a hinged portion 20 and reveals an opening 17 through top panel 12. A resealable cover 22 has a lower surface 24 disposed opposite an upper surface 26, which is configured and composed to receive printing (not shown) thereon. Cover 22 is configured and disposed to overlie and cover through-cut 16, opening 17, and flap 18. Lower surface 24 of cover 22 is provided with adhesive (indicated by stippling) 28 that permits cover 22 to be peeled away from top panel 12 and thereafter reseal the opening 17 defined through top panel 12 by through-cut 16. A plurality of knitted sheets 30 are stacked in the receptacle 15. A volatile organic compound is provided in receptacle 15 and saturates sheets 30. Such packages 10 have been used in health care environments, biological lab environments, "clean room" environments such as in semiconductor manufacturing, and other sterile environments. Other dispensing packages such as the package formed by a machine manufactured by the Hayssen Corporation, are configured having a polyester/polyethylene laminated sheet, which is wrapped about a stack of non-woven wipers and sealed at three locations, at its opposite ends and lengthwise where the edges overlap.